1. Field of the Invention
The field of the present invention is that of wiring and more particularly that of wiring of aircraft and their fastening.
2. Description of the Related Art
The structure of an aircraft is conventionally achieved by a series of circular frames, supported by longitudinal frame members and positioned evenly along the fuselage, to which bars called stringers are fastened. The skin of the aircraft is attached to this network of frames and stringers.
The cells of aircraft, whether they be airplanes or helicopters, are conventionally made of metal which has a certain number of advantages. In particular, the conductive character of metal makes it possible to achieve the following functions:                production of an electrical network for the return of current from the items of equipment of the airplane; the items of equipment are thus electrically connected, for the phase, to a wire carrying the electric current and, for the neutral, to the structure of the aircraft. There is therefore no need to put in place a specific current-return network.        common earthing of the items of equipment, which makes it possible to protect these items of equipment as well as the passengers,        creation of a common potential reference allowing the items of equipment to all have the same potential reference and to work in the same electrical voltage range,        protection, by a Faraday cage effect, against the direct and indirect effects of lightning which could injure the passengers and destroy the items of electrical equipment on board, and finally        production of effective electromagnetic protection against electromagnetic radiation; specifically, when an electrical conductor is subjected to an electromagnetic field, a voltage, called an induced voltage, appears between its two ends and may cause interference, or even damage to the electrical receivers that are connected thereto. These electromagnetic fields may be created either by the radiation of an antenna or of a radar (particular directional radiation), or by circulation currents due to lightning strike and which will travel over the surface (which is more or less conductive) of the structure of an airplane (indirect effects of the lightning), or else by currents of high intensity which travel in the power cables of the internal electrical network of the aircraft.        
The technology of aircraft cells has however evolved and the designers are turning increasingly to the use of composite materials which have good performance with respect to weight and mechanical strength and in particular to the use of carbon fibre composites.
The result of this is that the functions indicated above are no longer performed, the electrical conductivity of these composite materials being relatively low. It is therefore necessary, on aircraft made of composite material, to recreate the functions formerly performed by the metal structure of the aircraft. For this, a first evolution has been invented which consists of installing along the structure of the airplane metal or metalized cable supports in the form of trunking in which the electric cables are fastened. This linear trunking, with a U-shaped section, runs along the fuselage to perform the functions listed above. One example of such trunking is given by European Patent Application EP 0184931 by British Aerospace. In addition, European Patent Application EP1355397 by the British company C & C Marshall Ltd is known, which describes trunking connectors designed to cause cables to bend. Because of their small radius of curvature and their bulk associated with this radius of curvature, these connectors are not suitable for the installation of cables along or parallel to the frames of a fuselage, the radius of curvature of which is much larger. In addition, these bends place the cables between the trunking and the wall of the airplane, which is particularly harmful with respect to the risk of short-circuit on airplanes made of composite material as explained below.
In carbon fibre structures (or structures called CFRP) it is essential to prevent electric wires, even those in which low-intensity currents travel, from being able to come into contact with the structure. In case of breakage of a cable or a contact of this cable with the structure of the airplane, a short-circuit appears with which are associated a local heating and a possible catching-fire of the carbon and the resin contained by the structure. Such a phenomenon would cause the emission of toxic fumes for the passengers.
The problem is particularly acute for cables designed to follow a curved trajectory, like those mounted along the frames of the aircraft, or else those that are fastened to stringers and that run parallel to the frames of the aircraft. Aviation cables are usually relatively rigid and tend to resist the bending that they sustain. The stresses sustained, associated with the vibrations, may cause, with ageing, tears in the outer insulation and the breaking of a wire. The latter then stands up and can naturally come into contact with the skin of the airplane.
It is therefore appropriate to anticipate such a problem and to find a means for protecting the portions of an airplane made of carbon fiber against the inadvertent breakages of cables running along the frames of the airplane or parallel to the latter.